Book: The Placebo Effect in Sexual Medicine, dr. Frederik Feys

Cover The Placebo Effect in Sexual Medicine: Methodological Factors in Randomized Clinical TrialsThe Placebo Effect in Sexual Medicine
Methodological Factors in Randomized Clinical Trials

Paperback – 24 Nov 2015
by Frederik Feys (Author)

€18.5 (excl delivery), includes a pdf version

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Frederik Feys graduated as a dentist in 1997. He studied medicine for several years and holds a master’s degree in family and sexological sciences (2002). In 2015 he became Doctor in Medical Sciences.  In the clinical field he has been working since 12 years as a sex- and couple therapist. He applies the principles of autosuggestion in the form of self-help. His mission is to further explore how we can openly use the ‘vehicle’ behind the powerful placebo effect. So that clinicians can incorporate such effects in treatment decisions and patient counselling information. Ultimately improving the health and wellbeing of people.

Book Summary Medication side-effects can unblind randomized clinical trials (RCTs) that may result in misleading treatment effect estimates. Enhanced intervention blinding of people participating in an RCT can be achieved by using active placebo’s, a placebo that mimics side-effects of the intervention.

In the realm of sexual medicine, we found that such blinding-enhanced controlled RCTs for erection pills are absent. We also found a consistent failure to report on RCT blinding in journal publications. Clearly, the blinding efforts for almost all trials remain unclear. Our study found no conclusive evidence that unblinding leads to underestimating placebo effects or to the overestimation for intervention effects by investigators. Secondary analyses provided evidence that RCT participants with prior experience with the intervention reported substantially lowered placebo scores. It may be that participants with prior experience determine their allocation to placebo more efficiently and consequently engender lower expectancies as to their benefits.

After critical appraisal of the blinding status in studies for an ejaculation-delaying pill (dapoxetine), we found no evidence that dapoxetine is more effective than placebo. And dapoxetine comes with harmful effects. The blinding adequacy of almost all the studies remained unknown. The
methodology used in most studies was problematic due to incomplete data reporting, conflict of interests and selective reporting.

We conclude that methodological rigour in the conduct and reporting of RCTs is especially imperative for those health conditions that are evaluated
subjectively, such as depression, erectile dysfunction, low back pain, and many other symptom driven complaints.

Persbericht: Slikken we massaal placebo-geneesmiddelen?

Slikken we massaal placebo-geneesmiddelen?

Wanneer een geneesmiddel wordt getest, gebeurt dat vaak ‘dubbelblind’. Dat betekent, dat noch de onderzoeker, noch de testpersoon tijdens het experiment weet wie tot de experimentele, en wie tot de controlegroep behoort. Dat is belangrijk, omdat er op die manier placebo-effecten uitgesloten kunnen worden. Maar gebeuren die dubbelblinde studies ook echt altijd dubbelblind? Dat onderzocht Frederik Feys in zijn doctoraatsthesis.

Zijn onderzoek bekeek 222 wetenschappelijke artikels over erectiepillen en pillen bij te-snel-klaarkomen. Het wijst uit dat het goed mogelijk is dat proefpersonen achterhalen in welke testgroep ze zitten. Dat kan doordat mensen in de experimentele groep nevenwerkingen ervaren. Mensen in een placebo groep hebben die niet. Frederik Feys ontdekte dat hierover nauwelijks informatie wordt gepubliceerd in medische tijdschriften. Zonder deze informatie, kan de betrouwbaarheid van geneesmiddelen-onderzoek in vraag gesteld worden.

Het onderzoek draagt een duidelijke en belangrijke boodschap in zich: dat klinische studies moeten testen of ze dubbelblind gebeuren. Doen ze dat niet, of rapporteren ze hier niet over, dan is het mogelijk dat we massaal pillen slikken die feitelijk placebo pillen zijn met nevenwerkingen. Enkel door dit te testen, weten we zeker of geneesmiddelen effectief en veilig zijn.

PhD thesis, succesvol verdedigd op 24 november 2015
Vakgroep Huisartsgeneeskunde en Chronische zorg, Vrije Universiteit Brussel

The placebo effect in sexual medicine: methodological factors in randomized clinical trials. DOI: 10.13140/RG.2.1.3004.0406

Frederik Feys, MSc, PhD of 32488020010

Do randomized clinical trials with inadequate blinding report enhanced placebo effects for intervention groups and nocebo effects for placebo groups?

Here you can find our full reporting:

We found clear evidence that studies assessing a subjective continuous outcome fail to report on measures taken to secure double blinding. Although we observed a trend for the presence of a nocebo effect, there was insufficient evidence to quantify its impact on expectations. RCTs with patients with no prior experience with PDE-5 inhibitors reported larger placebo effects and possibly these studies were better blinded. Future research should further investigate the factors that contribute to blinding and their impact on health outcomes in randomized trials of subjectively assessed conditions.